IgE-Mediated Food Allergies - Continued
A wide variety of symptoms are associated with IgE-mediated food allergies. The symptoms can involve various systems of the body including the skin, respiratory tract, and gastrointestinal tract (6). The features and severity of the symptoms experienced depend on the nature of contact with the antigen, the dose of the offending food, and the degree of sensitization. Symptoms involving the gastrointestinal tract are common with food allergies, and include abdominal cramping and pain, diarrhea, vomiting, and nausea (6, 14). Symptoms involving the respiratory tract include sneezing, itching of the eyes, nose, as well as a runny nose (1, 6, 9). And although uncommon, food-induced asthma may also occur. Symptoms involving the skin can include urticaria, or hives, as shown in the animation, eczema, itching, or flushing. Other symptoms can include hypotension, swelling of the throat area, or even anaphylactoid shock (1).
The diagnosis of IgE-mediated food allergies can be difficult due to the wide variety of symptoms that can be involved. With the assistance of an allergist, along with several diagnostic tools and approaches, the proper diagnosis can be made. The diagnostic tools and approaches include a proper patient history; which should include specific information, everything from seasonal and locational variations in the symptoms, to exacerbating factors (1, 8, 9). Other diagnostic approaches include tests, such as skin testing, which involves introducing the allergen by pricking or puncture of the skin. There are in vitro tests, which detect the presence of IgE in the serum, through various assays such as ELISA (enzyme linked immunosorbent assay), RAST (radioallergosorgent test), and Basophil Histamine Release (8, 9). There are also challenge tests, which involve the ingestion or inhalation of the allergen, followed by monitoring for sign, symptoms, or reactions (1, 8, 9).